1. Field of the Invention
The instant invention relates generally to automatic shut-off devices and more specifically it relates to a stove emergency cutoff system. The stove emergency cutoff system will turn off electric or gas stoves if something cooking on the stove starts to burn and produce a large flame, which will activate the system.
2. Description of the Prior Art
Numerous automatic shut-off devices have been provided in prior art. For example, U.S. Pat. Nos. ,641,314 to Douvan; 4,070,670 to Chen; 4,491,142 to Shimizu and 5,400,766 to Dillon all are illustrative of such prior art. while these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described.
U.S. Pat. No. 2,641,314 discloses an automatic cutoff valve for fluid fuel burners, the combination with a valve casing in the conduit through which the fluid fuel is fed to the burner and a manually adjustable rotary valve in the valve casing, of a first rotary element in the form of a disc rigidly secured to the valve and provided with ratchet teeth on at least part of its periphery. A first spring urges the valve to its closed position. A detent is arranged to cooperate with the ratchet teeth on the disc to hold the valve in an open position. A second rotary element in the form of a cam is supported co-axially with and is rotatable relatively to the disc and valve. A second spring weaker than the first spring and urging the cam toward an angular position corresponds to that of the disc and valve. The cam has a raised portion for cooperation with the detent when the cam assumes an operative position corresponding to a predetermined opening of the valve, so as to release the disc and valve from the detent for return to the closed position of the valve. A delay mechanism is operatively associated with the cam, to delay movement of the latter from its position corresponding to the closed position of the valve to its operative position for a predetermined initial period after the valve has been opened. A thermostat is adapted to be installed adjacent the burner. A means is controlled by the thermostat and is operative if the thermostat has become heated by the burner flame prior to the end of the initial period and as long as the thermostat is heated to interfere with the movement of one of the rotary elements, so as to prevent release of the valve for return to the closed position.
U.S. Pat. No. 4,070,670 discloses a safety control shut-off device for the heating element of a cooking stove. In one embodiment of this safety device, a burner plate of the stove is provided with several declining U-shaped grooves for collecting any spillage or overflow of water from the cooking operations. Water drops collected in the declining grooves are led through a discharge outlet, at the lowest portion of the grooves, and into a water drop detector located beneath the outlet, to complete an electrical circuit, which in turn will actuate and sound an alarm and will also actuate means for disconnecting the fuel source of the plate burner.
U.S. Pat. No. 4,491,142 discloses an automatic fuel supply stopping device incorporated in fuel combustion equipment includes a shut-off valve and a combustor. The automatic fuel supply stopping device comprises a fluid intercepting mechanism interposed in a channel through which the fuel supply to the combustor is supplied. A photosensor is adapted to detect fuel combustion in the combustor by radiation emitted from a thermosensitive luminous medium. The fluid intercepting mechanism alternately takes its first stable state or passage blocking state and is changed over, in response to an output from a sensor circuit, from the passage opening state to the passage blocking state.
U.S. Pat. No. 5,400,766 discloses a gas appliance stove safety valve system that incorporates a safety valve assembly between the gas line manifold of the stove and the wall shut-off valve from the main gas line. The safety valve assembly is mounted adjacent the rear of the gas appliance stove beneath an aperture in its top wall. A special structure is utilized to fasten the ball valve assembly to the top wall of the stove. A special key is utilized that can be inserted through the aperture in the top wall of the stove to rotate the valve stem of the ball valve assembly between a closed position and an open position. There is also a structure for preventing removal of the key unless the safety valve assembly is actuated to its shut-off position.